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The Engine Overhaul Myth

by Peter Friedman published in AMT October 25, 2007

In order to discuss engine overhauls, we should start by looking at a few regulations. FAR 43.2 requires any “person” [defined at FAR 1] that describes a product as being “overhauled” in any required maintenance record [defined at FAR 43.9] to have “[used] methods, techniques, and practices acceptable to the Administrator ...” 

Overhauled vs Remanufactured

Further, the product must have been “...disassembled, cleaned, inspected, repaired as necessary, and reassembled ...” After reassembly, the product must be “... tested in accordance with [FAA] approved [defined at FAR 1] standards and technical data [read overhaul agency such as a repair station], or in accordance with current standards and technical data acceptable to the Administrator, which have been developed and documented by the holder of the type certificate [read Lycoming or Continental for example]...”

For the sake of argument here let us agree that we are describing an “overhauled” engine, not a factory remanufactured engine. Only a factory remanufactured engine may be "zero-timed" with a completely new, fresh logbook without records of previous service history or engine total time. Information on factory remanufactured engines, legally referred to as "rebuilt", may be found in FAR 91.421 and FAR 43.2(b). Additionally, there are no such legal overhauls as “top” or “bottom!” These are repairs because there is no data available that complies with FAR 43.2(a) concerning such work.

The aircraft owner ready to overhaul an engine therefore must literally walk through a minefield to get to the truth about engine overhaul possibilities.

Factory Remanufactured or Rebuilt engine.

Overhauled aircraft Engine

Finding the right Overhaul Agency

The first thing aircraft owners should consider when looking for an overhaul agency is if they are rated for the work. An FAA certificated powerplant mechanic can overhaul a complete engine and legally approve it for return to service. In fact, there are a number of engine overhaul shops that aren’t repair stations but rather operate with certificated mechanics. A review of the Maintenance Release statement entered in the engine log at the overhaul completion easily reveals this. The release is signed by a mechanic along with his/her certificate number. If you have a problem with this overhaul guess where your recourse lies? Further, these agencies do NOT get any FAA scrutiny such as repair stations do, albeit infrequently. The only time the FAA gets involved with an individual mechanic is by specific complaint or body count! If you have a problem with the company that employed the mechanic, the FAA can not proceed against them, only the individual. You now must contemplate a civil fraud action or small claims action. The company, of course, will attempt to lay the blame at the feet of the mechanic who signed off the overhaul. The company will cite FAR 43.7 laying the responsibility on the individual because the company is NOT certificated. The FAA will have to defend the company's position legally. (A repair station is held co-liable with their employees because FAR 145 requires a repair station to supervise the employees.)

Obviously, the choice of an appropriately rated repair station is the better one. (This does NOT imply that you can't get a decent overhaul from an individual mechanic!) There are problems with repair stations as well though. You do NOT always get what you pay for, or think you are paying for.

Right up front you should get in writing from a repair station (and an individual mechanic) exactly what technical data they intend to use to overhaul your engine. Further, get in writing exactly what minimum parts they will replace AND where they intend to get them from!!! Are the parts they intend to use genuine factory parts, or are they going to be cheaper PMA parts? Would you believe that repair stations flat rate overhauls based upon factory part prices and then install cheaper PMA parts without your knowledge or consent! How many owners actually audit the repair invoices or ask where the parts are coming from? (The use of PMA parts without your knowledge or consent is absolutely legal with respect to the FAR! You have no complaint to the FAA on this issue if the parts installed have an FAA approval basis. Your argument would again be civil fraud, but the FAA would again back the overhaul agency's use of FAA approved parts. Some game, huh?)

Remember FAR 43.2 and the words "inspected" and "repaired as necessary"? Look out! Inspected and repaired as necessary in accordance with what? In accordance with FAA approved data OR the engine type certificate holder's data. Go back to the beginning and reread the first paragraph. It says it all. If you understand it you can't be fooled. FAR 43.9 describes the records required for "maintenance" [defined at FAR 1] which include "inspection, overhaul, repair...and the replacement of parts." Is this not what is required when overhauling an engine? You bet it is! The records for your engine overhaul MUST comply with FAR 43.9 for each of these activities. It would be perfectly legal for a certificated person under FAR 43.7 to sign a complete engine overhaul off for return-to-service with the simple statement, "I certify that I overhauled this engine in accordance with the [specific type certificate holder] overhaul manual number [show manual number]." All of the requirements of FAR 43.9 are met, i.e. description of the work performed [overhauled], and reference to [FAA] acceptable data [the TC holder's overhaul manual]. In fact, I prefer to audit log records such as this because it is very easy to use the TC holder's data as a checklist. Didn't the statement certify the use of the data? If the work doesn't conform to the data, voila! You caught them. "Inspection" as described in FAR 43.2(a) means inspection to the data described in the return-to-service approval statement. What about "repaired as necessary" though? This gets tricky and here is where most fraud takes place.

Repaired as necessary

"Repaired as necessary" means in accordance with technical data, not the whim or best guess of a mechanic. Is the "repair" major or minor [defined at FAR 1 and at FAR 43, Appendix A]? There are specific repairs shown in TC holder's overhaul manuals, and some constitute major repairs. Guess what? Most overhaul manuals are FAA approved because major repairs require ONLY FAA approved data! (Major repairs always require a Form 337; however, repair stations are granted a deviation allowing them to record major repairs on workorders, in accordance with FAR 43, Appendix B, PROVIDED the customer receives a SIGNED copy of the workorder. Again, all requirements for recording repairs during overhaul must meet FAR 43.9 record requirements. 

Custom Color Electrostatic Powder Coated - Aircraft Engine Overhaul

Beware of Specials

Now it gets more complicated.... There are repair stations out there who advertise "special" processes that entice owners to use their agencies over some other. The engine overhaul business is very competitive! However, here is where more fraud can take place. "Special" processes deviate in most cases from the TC holder's overhaul data; otherwise they wouldn't be called "special". Please be advised that ALL PROCESSES accomplished by ANY FAA certificated repair station MUST be FAA approved!!! In fact, FAR 145.61 specifically requires [using the word "shall" defined at FAR 1.3 as being "imperative"] that ANY PROCESS used MUST BE LISTED on the repair station's FAA approved Operations Specifications. 


Now we are down to the real meat of the engine overhaul minefield! How many ads are there in aviation magazines for special engine paint schemes such as powder coating? Perhaps an ad or two for chrome or nickel plating rocker covers and hardware? There is even an ad for 24K gold plating rocker covers! How about ads for Parkerizing internal engine parts? Further, ads exist that describe a process whereby connecting rods and other internal parts are subjected to metal removal to balance the components to each other. NONE of these processes usually appear in the TC holder's data. ALL of these processes are required to be on the repair station's Operations Specifications if they use them! (Obviously, get a copy of the Ops Specs before you contract for the overhaul!)


Don't be fooled! FAR 43. Appendix A, section (b)(2) specifically describes as a "major" repair "Special repairs to structural engine parts by welding, plating, metalizing, or other methods." (Emphasis added) Common sense dictates that the nickel plating of crankcase attachment hardware is STRUCTURAL!!! Further, taking the used hardware from the engine and having it replated, even with the same cadmium treatment, IS A PROCESS! It must be approved AND the repair station must be approved to use it unless it specifically appears in the TC holder's technical overhaul data. (Guess what? Most TC holders want you to use all new hardware!)


Do your homework first!

Most TC holders, such as Lycoming and Continental, publish service literature that describes their recommendations for minimum parts replacement at overhaul. Lycoming publishes, for example, Service Bulletin No. 240 and Continental publishes Service Bulletin M87-11 listing the replacement parts. THESE ARE FREE! Just call them. Use them as a checklist with the overhaul records you receive to see if they were complied with. Better yet, make them requirements of your overhaul contract! GET IT IN WRITING! Remember, the FAA protects itself first, certificated people second, AND YOU THIRD. The FAA can not do anything to any person [defined at FAR 1] unless they are certificated! It is the FAA's responsibility to catch certificated bad guys before you do. The FAA is always embarrassed when someone they are supposed to be responsible for has been caught cheating. It makes them [FAA] look bad.


Engine overhauls are like real estate; if it isn't in writing, it didn't happen! It might behoove owners looking for an engine overhaul to seek the services of an FAA Designated Airworthiness Representative (DAR) for a few hundred dollars to research the capabilities of any specific agency BEFORE they do they work. After all, if an overhaul can cost upwards of $30,000, a few hundred dollars is less than 1% to have the assurance that you won't get ripped off, or worse, perhaps DEAD! You can also inquire at the agency's local Flight Standard District Office to see if they have a violation history? You may have to do this under Freedom of Information because the FAA doesn't like to give out "safety" information without a fight unless the information is positive.

Lastly, please read the warranty BEFORE you contract for the overhaul. Most warranties, other than from the TC holder directly, are absolute crap! They use words such as "remanufactured" and "rebuilt" implying that the engine will be good as new. This is patently baloney if you read the first paragraph of this article again where FAR 43.2(a) is quoted. Nothing needs to be done on an overhaul except to disassemble, clean, inspect, repair as necessary, and reassemble the engine! Get real! There is NO MAGIC! When it hits the proverbial fan, who do you want standing next to you in Court? An individual mechanic or fly-by-night repair station? Or do you want the factory? Who has the most assets? The extra money you pay to get the job done right is good insurance. But make no mistake about what is "right". Your life and the lives of your loved ones may depend upon the honesty and integrity of the person overhauling that engine. Choose your engine overhauler with at least the same critical eye that you would use to choose your friends, your doctor, or the lawyer that will represent you after you get ripped off!         



Peter M. Friedman is the owner of Friedman Aviation Enterprises in Concord, CA, an FAA Repair Station FQVR855X. In addition, Mr. Friedman is an A&P/IA for over 25 years, as well as instructing an IA Refresher Seminar on the FARs for over 16 years. Mr. Friedman is a contributor to many aviation industry magazines. 

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